From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLACK autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2656BC433E0 for ; Mon, 8 Jun 2020 12:14:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E2293206C3 for ; Mon, 8 Jun 2020 12:14:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="FpMLK4cy" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729744AbgFHMOg (ORCPT ); Mon, 8 Jun 2020 08:14:36 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:58236 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729644AbgFHMOf (ORCPT ); Mon, 8 Jun 2020 08:14:35 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1591618473; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=n0WTesSFX4GdOnD7OP8HwiFpZRIS/BtZoZgv9wJXix0=; b=FpMLK4cysvzA2/JuboYEUkDTyjAIV/Pjs0/5abTN9g4cBO9GjgPWFXu9wfPrKFMuEhHN7e 8bcUSoqcafEO8sxRlQNnrDCTrclmVmj6PCS24u/yG7Z67ZXPTACUyB/f57nZjXhjJ4GZVl 58c5zFI+0E2uH6Y1CRF7fOsCw4fQrZc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-168-MXyvpYL0M9uFpPHUudC0sA-1; Mon, 08 Jun 2020 08:14:31 -0400 X-MC-Unique: MXyvpYL0M9uFpPHUudC0sA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D50DB8014D4; Mon, 8 Jun 2020 12:14:30 +0000 (UTC) Received: from virtlab701.virt.lab.eng.bos.redhat.com (virtlab701.virt.lab.eng.bos.redhat.com [10.19.152.228]) by smtp.corp.redhat.com (Postfix) with ESMTP id 326FC619C4; Mon, 8 Jun 2020 12:14:29 +0000 (UTC) From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: vkuznets@redhat.com, Qian Cai Subject: [PATCH] KVM: SVM: fix calls to is_intercept Date: Mon, 8 Jun 2020 08:14:28 -0400 Message-Id: <20200608121428.9214-1-pbonzini@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org is_intercept takes an INTERCEPT_* constant, not SVM_EXIT_*; because of this, the compiler was removing the body of the conditionals, as if is_intercept returned 0. This unveils a latent bug: when clearing the VINTR intercept, int_ctl must also be changed in the L1 VMCB (svm->nested.hsave), just like the intercept itself is also changed in the L1 VMCB. Otherwise V_IRQ remains set and, due to the VINTR intercept being clear, we get a spurious injection of a vector 0 interrupt on the next L2->L1 vmexit. Reported-by: Qian Cai Signed-off-by: Paolo Bonzini --- Vitaly, can you give this a shot with Hyper-V? I have already placed it on kvm/queue, it passes both svm.flat and KVM-on-KVM smoke tests. arch/x86/kvm/svm/nested.c | 2 +- arch/x86/kvm/svm/svm.c | 4 +++- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 8a6db11dcb43..6bceafb19108 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -258,7 +258,7 @@ void sync_nested_vmcb_control(struct vcpu_svm *svm) /* Only a few fields of int_ctl are written by the processor. */ mask = V_IRQ_MASK | V_TPR_MASK; if (!(svm->nested.ctl.int_ctl & V_INTR_MASKING_MASK) && - is_intercept(svm, SVM_EXIT_VINTR)) { + is_intercept(svm, INTERCEPT_VINTR)) { /* * In order to request an interrupt window, L0 is usurping * svm->vmcb->control.int_ctl and possibly setting V_IRQ diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 9e333b91ff78..c8f5e87615d5 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -1378,6 +1378,8 @@ static void svm_clear_vintr(struct vcpu_svm *svm) /* Drop int_ctl fields related to VINTR injection. */ svm->vmcb->control.int_ctl &= mask; if (is_guest_mode(&svm->vcpu)) { + svm->nested.hsave->control.int_ctl &= mask; + WARN_ON((svm->vmcb->control.int_ctl & V_TPR_MASK) != (svm->nested.ctl.int_ctl & V_TPR_MASK)); svm->vmcb->control.int_ctl |= svm->nested.ctl.int_ctl & ~mask; @@ -1999,7 +2001,7 @@ void svm_set_gif(struct vcpu_svm *svm, bool value) */ if (vgif_enabled(svm)) clr_intercept(svm, INTERCEPT_STGI); - if (is_intercept(svm, SVM_EXIT_VINTR)) + if (is_intercept(svm, INTERCEPT_VINTR)) svm_clear_vintr(svm); enable_gif(svm); -- 2.26.2